CN6035 Hybrid Crowdfunding DApp

This repository contains the CN6035 Mobile and Distributed Systems coursework implementation based on the open-source project:

https://github.com/spandan114/Crowdfunding-DAPP

The initiative is a decentralised application (DApp) for crowdfunding. Users may establish fundraising campaigns, donate ETH using MetaMask, and authorise withdrawal requests by contributor voting. The application integrates a web front end with Solidity smart contracts executed on a local Hardhat blockchain.

Coursework Relevance

The project maps to the CN6035 assessment criteria as follows:

Assessment area	Evidence in this repository
Back-end implementation	Solidity contracts in contracts/Crowdfunding.sol and contracts/Project.sol implement campaign creation, contribution handling, project state, withdrawal requests, and contributor voting.
Blockchain interaction	Hardhat is used for compilation, testing, local blockchain execution, and contract deployment. The frontend connects to the deployed contract through Web3.js and MetaMask.
Front-end implementation	The client folder contains a Next.js/React interface with dashboard, campaign creation, contribution, project details, and withdrawal request pages.
Code quality and version control	The project includes contract tests, ESLint checks, a verification document, and coursework-specific commits showing the changes made for the assessment.

Main Technologies

• Solidity
• Hardhat
• ethers.js
• Web3.js
• MetaMask
• Next.js
• React
• Redux
• Tailwind CSS
• Chai / ethereum-waffle

Project Structure

.
|-- client/                  # Next.js frontend
|-- contracts/               # Solidity smart contracts
|-- scripts/                 # Hardhat deployment scripts
|-- test/                    # Hardhat contract tests
|-- COURSEWORK_VERIFICATION.md
|-- hardhat.config.js
|-- package.json

Smart Contract Summary

Crowdfunding.sol works as the project factory and registry. It creates new Project contracts, stores the list of created projects, and forwards user contributions.

Project.sol stores the core campaign logic:

• campaign creator
• minimum contribution
• campaign deadline
• target contribution
• raised amount
• contributor count
• project state: Fundraising, Expired, or Successful
• withdrawal request data
• contributor votes

The withdrawal process requires contributor approval before funds are released, which demonstrates blockchain-based rule enforcement and shared distributed state.

Front-End Summary

The frontend is implemented in the client directory. Important areas include:

• pages/dashboard.js: displays projects and contribution actions
• pages/project-details/[id].js: displays project details and withdrawal requests
• pages/my-contributions.js: displays the connected user's contributions
• components/FundRiserForm.js: creates new fundraising campaigns
• components/FundRiserCard.js: displays campaign state and contribution controls
• redux/interactions.js: handles Web3.js contract interaction

Coursework Changes Made

The original repository was adapted and verified for the 2026 coursework environment:

• Fixed stale 2022/2023 test deadlines by replacing them with future timestamps, allowing the test suite to run correctly in 2026.
• Added a MetaMask availability guard in _app.js so the application no longer crashes when opened in a browser without an injected window.ethereum provider.
• Removed a synchronous external Font Awesome script and replaced the mobile menu icon with a local character.
• Added passHref to Next.js Link components where required.
• Escaped an apostrophe in JSX to satisfy React linting.
• Added *.log to .gitignore.
• Added COURSEWORK_VERIFICATION.md with verification results and local demo notes.

Installation

Install root dependencies:

npm.cmd install

Install frontend dependencies:

cd client
npm.cmd install

Compile and Test

From the repository root:

npx.cmd hardhat compile
npx.cmd hardhat test

Verified result:

15 passing

Hardhat may show a Node.js compatibility warning on Node.js 22 because this is an older Hardhat project. The contracts still compile and the tests pass locally.

Run Locally

Start the local Hardhat blockchain:

npx.cmd hardhat node

Deploy the crowdfunding contract:

npx.cmd hardhat run scripts/deploy.js --network localhost

The local deployment address used by the frontend is:

0x5FbDB2315678afecb367f032d93F642f64180aa3

Start the frontend:

cd client
$env:NODE_OPTIONS="--openssl-legacy-provider"
npm.cmd run dev

Open:

http://localhost:3000

MetaMask Local Network

Use these settings:

• Network name: Hardhat Localhost
• RPC URL: http://127.0.0.1:8545
• Chain ID: 31337
• Currency symbol: ETH

Import one of the Hardhat test accounts printed in the terminal. These accounts are public development accounts and must never be used on mainnet.

Verification Results

The following checks were completed locally:

Check	Result
npx.cmd hardhat compile	Passed
npx.cmd hardhat test	Passed with 15 passing
npx.cmd eslint . in client	Passed with warnings only
npm.cmd run build in client	Passed with NODE_OPTIONS=--openssl-legacy-provider
Local frontend runtime	HTTP 200 at http://127.0.0.1:3000
UI demo flow	Created a campaign and contributed ETH through the local frontend

Known Limitations

• The project uses older dependencies and npm audit reports vulnerabilities.
• The Hardhat version is old and warns when used with Node.js 22.
• The frontend requires the OpenSSL legacy provider flag on modern Node.js.
• The local contract address is hardcoded in client/redux/interactions.js.
• ESLint reports remaining React hook dependency warnings.

These limitations are discussed in the coursework technical report as part of the code quality and critical evaluation sections.